fix(telegram): retain socket failure context (#97130)

Co-authored-by: zhang-guiping <zhang.guiping@xydigit.com>

extensions/telegram/src/fetch.test.ts

@@ -957,7 +957,7 @@ describe("resolveTelegramFetch", () => {
     expect(eighthDispatcher).toBe(firstDispatcher);
     expect(ninthDispatcher).toBe(firstDispatcher);
     expectPinnedFallbackIpDispatcher(3);
-    expectLoggerMessageContaining(loggerWarn, "fetch fallback: DNS-resolved IP unreachable");
+    expectLoggerMessageContaining(loggerWarn, "fetch fallback: primary connection path failed");
     expectLoggerMessageContaining(
       loggerDebug,
       "fetch fallback: recovered from attempt 2 to attempt 0",
@@ -1193,6 +1193,31 @@ describe("resolveTelegramFetch", () => {
     expect(undiciFetch).toHaveBeenCalledTimes(1);
   });
 
+  it("does not automatically retry structured EADDRNOTAVAIL fetch failures", async () => {
+    const fetchError = buildFetchFallbackError("EADDRNOTAVAIL");
+    undiciFetch.mockRejectedValue(fetchError);
+
+    const resolved = resolveTelegramFetchOrThrow(undefined, STICKY_IPV4_FALLBACK_NETWORK);
+
+    await expect(resolved("https://api.telegram.org/botx/sendMessage")).rejects.toThrow(
+      "fetch failed",
+    );
+
+    expect(undiciFetch).toHaveBeenCalledTimes(1);
+  });
+
+  it("preserves EADDRNOTAVAIL in forced fallback diagnostics", () => {
+    const transport = resolveTelegramTransport(undefined, STICKY_IPV4_FALLBACK_NETWORK);
+    const fetchError = buildFetchFallbackError("EADDRNOTAVAIL");
+
+    expect(transport.forceFallback?.("probe timeout/network error", fetchError)).toBe(true);
+    expect(transport.forceFallback?.("probe timeout/network error", fetchError)).toBe(true);
+
+    expectLoggerMessageContaining(loggerWarn, "primary connection path failed");
+    expectLoggerMessageContaining(loggerWarn, "codes=EADDRNOTAVAIL");
+    expectNoLoggerMessageContaining(loggerWarn, "DNS-resolved IP unreachable");
+  });
+
   it("retries sticky fallback when the local network is down during connect", async () => {
     undiciFetch
       .mockRejectedValueOnce(buildFetchFallbackError("ENETDOWN"))

extensions/telegram/src/fetch.ts

@@ -488,9 +488,10 @@ export type TelegramTransport = {
   dispatcherAttempts?: TelegramDispatcherAttempt[];
   /**
    * Promote this transport to its next fallback dispatcher before the next
-   * request. Returns false when no fallback path exists.
+   * request. The original error, when available, is retained in diagnostics.
+   * Returns false when no fallback path exists.
    */
-  forceFallback?: (reason: string) => boolean;
+  forceFallback?: (reason: string, err?: unknown) => boolean;
   /**
    * Release all dispatchers owned by this transport and the TCP sockets they
    * hold. Safe to call multiple times; subsequent calls resolve immediately.
@@ -563,7 +564,8 @@ function createTelegramTransportAttempts(params: {
     },
     exportAttempt: { dispatcherPolicy: fallbackIpPolicy },
     logLevel: "warn",
-    logMessage: "fetch fallback: DNS-resolved IP unreachable; trying alternative Telegram API IP",
+    logMessage:
+      "fetch fallback: primary connection path failed; trying alternative Telegram API IP",
   });
 
   return attempts;
@@ -864,8 +866,8 @@ export function resolveTelegramTransport(
     fetch: resolvedFetch,
     sourceFetch,
     dispatcherAttempts: transportAttempts.map((attempt) => attempt.exportAttempt),
-    forceFallback: (reason: string) =>
-      promoteStickyAttempt(stickyAttemptIndex + 1, new Error("forced fallback"), reason),
+    forceFallback: (reason: string, err?: unknown) =>
+      promoteStickyAttempt(stickyAttemptIndex + 1, err ?? new Error("forced fallback"), reason),
     close,
   };
 }

extensions/telegram/src/probe.test.ts

@@ -362,7 +362,7 @@ describe("probeTelegram retry logic", () => {
 
       const result = await probePromise;
       expect(result.ok).toBe(true);
-      expect(localForceFallback).toHaveBeenCalledWith("probe timeout/network error");
+      expect(localForceFallback).toHaveBeenCalledWith("probe timeout/network error", timeoutError);
       expect(fetchMock).toHaveBeenCalledTimes(3); // 1 failed + 1 getMe success + 1 webhook
     } finally {
       vi.useRealTimers();

extensions/telegram/src/probe.ts

@@ -162,7 +162,8 @@ export async function probeTelegram(
         // On timeout or network error, promote the transport to its IPv4
         // fallback dispatcher so the next retry (and all future probes
         // sharing this cached transport) skip the stalled IPv6 path.
-        transport.forceFallback?.("probe timeout/network error");
+        // Keep the original socket code in transport fallback diagnostics.
+        transport.forceFallback?.("probe timeout/network error", err);
         if (i < 2) {
           const remainingAfterAttemptMs = resolveRemainingBudgetMs();
           if (remainingAfterAttemptMs <= 0) {